In order to provide communication services using a telecommunications network, operators of telecommunications network are offering network services that assist subscribers with call establishment. Examples of such services include voice assisted dialing, and directory assisted dialing, the latter either with or without automatic call connect. These services entail that the subscriber dials a service number, and is connected to the network service or assistance entity facilitating the service. The subscriber may, in case of voice assisted dialing, pronounce the number or, in case of directory assisted dialing, pronounce the name of the desired destination party. The network service then retrieves the required destination identifier (e.g. telephone number) of the destination party, and dependent on the service either returns the destination identifier to the calling party, or (in case of automatic call connect and voice assisted dialing) connects the calling party to the destination party, or both.
The above described services suffer from a number of disadvantages as will be explained below.
In case of voice assisted dialing, or directory assisted dialing with automatic call connect, a disadvantage of these services is that the routing of the call through the telecommunications network is not performed in an efficient manner. The call is typically routed from a network node to which the assistance entity is connected, or from which the network service is initiated. From this network node, the call is routed or forwarded to the required destination. It is noted that rerouting of the call from this network node, is not necessarily the most efficient path through the network. To give an example, suppose the calling party and the destination party are connected to the same local network node, and the assistance entity facilitating the service is connected to a remote network node, the call from the calling party to the destination party is routed from the local network node, to the remote network node, back to the local network node, and to the destination party. In this case, the call is using the branch between the local network node and the remote network node twice (to and from the remote network node), while the most efficient routing of the call would not even use this branch (in fact would not use any branch in the network).
Another disadvantage of the voice assisted calling service or directory assisted calling service with automated call connect, is that charging of these call becomes unnecessarily complex on behalf of the network operator. In particular where the calling party is, for example, a prepaid subscriber, the local network node will only know the dialled number which is the service number. The eventual destination of the call between the calling party and the destination party is unknown, and this problem has to be resolved at a later stage in order to effectively charge the call.
Other, similar services include for example directory assistance calling without automatic call connect. In this case, the calling party establishes an operative connection with the assistance entity, and provides the assistance entity with (for example) the name of the destination party. The assistance entity returns the destination number to the calling party, either by mentioning the destination number to the calling party using an open voice service call, or differently by sending an SMS-message (Short Messaging Service (SMS)) to the calling party including the destination number.
A disadvantage of this type of service is that, where the destination number is provided through an ongoing voice service call, e.g. by pronouncing the destination number, the user has to memorize the destination number and subsequently dial the number on his telephone. Not only is this cumbersome to the calling party, but in case of a communicational error (e.g. the user has misinterpreted the destination number as it is pronounced), setting up the call may fail. Even a step of writing down the destination number does not completely eliminate this risk.
On the other hand, there where the destination number is provided by sending a short messaging service-message (SMS-message), a disadvantage is that the transmission of an SMS-message puts an additional demand on the network resources, since it is an additional communication service to be provided through the telecommunications network.
Another disadvantage of sending the destination number by SMS, is that for establishing a call to the destination party, user intervention is required. The SMS must be opened by the user, and the destination number must be called by the user.